Thought that I would share some info on the mythical/magical green impeller. When I was searching to buy my boat, I had read about these green impellers. So, I always asked the seller if their ballast pumps had the green impellers. Every time they looked at me with a blank face, no idea what I meant. My boat came with a spare, but broken down, Jabsco pump. I repaired the pump which had a used yellow impeller in it. My seller also had a spare brand new yellow impeller. I was bored at work one day, so I started doing some research on the mythical green impeller. I tracked down the product specialist at Jabsco. He told me that both the yellow and green impellers were both made from polyurethane. To his knowledge there was no difference in the impellers besides the color. He said that Jabsco buys the impeller from a vendor. One day that vendor informed Jabsco that the impellers would start coming in green. The Jabsco part number for the impeller didn't change with the color. Per this guy, the green impeller was form, fit, and function the same as the yellow and this is why they kept the same part number.

So, I did a test with my spare pump. I tested a used yellow that was in the old pump, a new yellow, and a new green. (The used yellow was actually still in good shape.) I just attached some black heater hose to the pump and used my truck battery to run the pump. I had two Rubbermaid totes with one filled with 10.5 gallons of water. I ran each impeller forwards and backwards twice, so each impeller had 4 runs to average against. Here are the results.

Used yellow: 57 sec average
New yellow: 59 sec average
New green: 56 sec average

Now, for the engineers in the bunch (which I am one), this was not in anyway a laboratory setting, I will admit. My 13 year old was running the stop watch for me, so there is probably a little error in here.

Conclusion: I really didn't see any significant difference in the fill rate between the yellow and green. Both seemed to prime equally well when the pump was dry. This makes me believe that the Jabsco guy was correct. The Jabsco pumps are rated for 11GPM, so this matched up pretty well with my results of about 10.8GPM. From my calculations, this would fill up a 500 lb ballast tank in 5.7 minutes.

I also measured the new yellow and green impellers with Mitutoyo calipers. The height difference was approximately .001" (negligible). The outside diameter of the yellow impeller was actually larger than the green one. Yellow was 2.015" versus 1.095" for the green (.020" difference).

I have read that the green is supposedly better at preventing the ballast tanks from emptying once filled. I personally don't see how the green would be any better than the yellow on this front. Maybe the green is a different durometer than the yellow. To the touch, I can't tell a difference. I wish I had a way to truly measure the durometer.

Anyway, just some info from someone that had too much free time, which is actually pretty rare for me.

AlbertaSurfer

11-19-2013, 10:53 PM

I thought the green ones were Nitrile, and the only benefit was they could run longer dry without breaking down? Like if you accidently left a ballast pump running. WakeMakers told me they only sell their pumps with the Nitrile impellors, but mine showed up with the regular ones.

Either way, sounds like they're the same thing in the end, good info.

Tristarboarder

11-19-2013, 11:31 PM

Great post! Thanks for taking the time to test and post results...

BudmanV24

11-19-2013, 11:42 PM

Whether there is any truth in it at all, I was told that the black impellars were really stiff and pumped quickly, but burned up in no time when ran dry. The yellow was released to prevent smoking the impellars when dry but on the other hand, had issues with allowing water to siphon past the impellar. Then came the green that was supposed to be a balance between the two. All of this is second...well maybe third hand information, so take it with a drop of teak oil.

Or the conspiracy theorist could propose that the entire ordeal has been a marketing campaign to increase sales of impellars. You decide.

Btw, have you heard of the new red impellars?

AlbertaSurfer

11-19-2013, 11:57 PM

I invented the red ones. They fill your ballast WITHOUT EVEN PUMPING WATER!

But, they squeal really loud, so anyone wanna get on making some purple ones?

blackhawk

11-20-2013, 12:49 AM

Albertasurfer - If you pull up the datasheet for the Jabsco pump it has a parts breakdown and gives the part number for the black and yellow impellers. The black one is listed as Nitrile and the Yellow/Green one is listed as polyurethane.

BudmanV24 - Yea, I thought the same thing about the yellow to green being just a marketing ploy. It probably works, change the color and start a buzz about the newest and greatest impeller has just came out. If there was a marketing ploy, I think the impeller vendor or the retailers probably ran that show instead of Jabsco. You can't blame them, really.

AlbertaSurfer

11-20-2013, 01:40 AM

WakeMakers claims the black and yellow impellers to be discontinued, but still list the green one as a "Premium Upgrade". Seems funny that it's an upgrade if it's the only impeller that Jabsco offers. They sell the green "Premium" one for $26. What were the others worth?

snork

11-20-2013, 09:45 AM

about half the price for the black ones

MattsCraft

11-20-2013, 10:10 AM

Blackhawk - Your science test seems rock solid.

No clue if there is any difference, yellow to green. All I can add is on my '09 X2, it came with yellow, was having the dreaded siphoning issue, dealer changed them to green under warranty per MC FCO and never had a problem with siphoning after the change.:D

BudmanV24

11-20-2013, 12:38 PM

Blackhawk - Your science test seems rock solid.

No clue if there is any difference, yellow to green. All I can add is on my '09 X2, it came with yellow, was having the dreaded siphoning issue, dealer changed them to green under warranty per MC FCO and never had a problem with siphoning after the change.:D

I spun/stripped the yellow impellar on the motor spline for my KGB tank. Switched to green and fill time improved dramatically. But, the old impellar was so worn it was nearly void of the ridges or whatever you want to call them at the end of each flappy thing. Yeah, I'm a mechanical engineer....

When surfing my rear tanks equalize due to I assume water siphoning through the pumps. Those yellow impellars are well worn too. I'm going to replace them this winter and if I remember I'll post an update come spring.

blackhawk

11-20-2013, 01:55 PM

I think that the biggest cause of the siphoning would be worn impellers. The impellers are only about .030" larger on the diameter than the pump housing. So, you only have to wear down .015" on the tips to be at a line to line fit. As soon as you wear past that point it will probably start leaking back through the pump.

Mattscraft - Do you remember how many hours you had on the yellow ones before the dealer replaced them?

Albertasurfer - I have seen on some websites where you can still buy the black nitrile impellers. One place that I saw had them for $23. Nitrile actually has a little higher temp rating than polyurethane. But polyurethane is much stronger and abrasion resistant.

CantRepeat

11-20-2013, 02:26 PM

Albertasurfer - If you pull up the datasheet for the Jabsco pump it has a parts breakdown and gives the part number for the black and yellow impellers. The black one is listed as Nitrile and the Yellow/Green one is listed as polyurethane.

BudmanV24 - Yea, I thought the same thing about the yellow to green being just a marketing ploy. It probably works, change the color and start a buzz about the newest and greatest impeller has just came out. If there was a marketing ploy, I think the impeller vendor or the retailers probably ran that show instead of Jabsco. You can't blame them, really.

The product specialist at Jabsco told me that both the green and yellow impellers were polyurethane. Also, the Jabsco datasheet for the 18220 pumps lists them as polyurethane. Nitrile is a synthetic rubber, usually in the form of Buna-N. It's biggest use is for O-rings. The green impeller does not look or feel like Nitrile IMHO.

The materials engineer where I work actually has a durometer tester. He is going to test the yellow and green impellers for me tomorrow. That will be a big piece of the puzzle to know.

CantRepeat

11-20-2013, 05:28 PM

The product specialist at Jabsco told me that both the green and yellow impellers were polyurethane. Also, the Jabsco datasheet for the 18220 pumps lists them as polyurethane. Nitrile is a synthetic rubber, usually in the form of Buna-N. It's biggest use is for O-rings. The green impeller does not look or feel like Nitrile IMHO.

The materials engineer where I work actually has a durometer tester. He is going to test the yellow and green impellers for me tomorrow. That will be a big piece of the puzzle to know.

All that could be true. Maybe it's possible that the nitrile(black) impeller is left over advertising that after market vendors just haven't moved away from.

MattsCraft

11-20-2013, 06:42 PM

Mattscraft - Do you remember how many hours you had on the yellow ones before the dealer replaced them?

Not many, it was in the first season (prob about 10) and did not have any overflow bags in yet. The siphoning only happened on the rears, never the KGB.

uplander

11-20-2013, 08:42 PM

I switched to green after reading threads on this forum, it looked my old yellow ones were still factory.

I also called Jabsco and asked about the polishing of the pumps and they said do not spend the time as polishing would not help

Can you do a study also with polishing the pumps :)

blackhawk

11-22-2013, 12:59 PM

Alright, the durometer tests are in, my guy used the Shore A scale. The green measured 75 and the yellow 70. A slight difference, but with only measuring one piece of each it is hard to know for sure if the green is truly stiffer. The tester has a +/-1 accuracy. My materials engineer also said that most materials like this will vary by +/-2.5 on the Shore scale from batch to batch. We could have caught the yellow on the low side and the green on the high side, really don't know. If we had 10 pieces of each to test, we could get a real trend.

Bottom line, the durometer from yellow to green is very similar. 5 points on the durometer scale is not a remarkable difference.

BudmanV24

11-27-2013, 01:25 AM

I had trouble when reversing the pump direction with the black ones. I had to remove the impeller and manually reverse the direction of the impeller vanes several times.

That would support what if been told, which is that the black impellars were extremely stiff.